Sydney sells more homes under the hammer than almost anywhere else in the country, so if you're buying here, you'll meet the auction sooner or later. The trouble is that the process is rarely explained end to end - buyers pick it up in fragments, standing on a footpath watching one unfold. This is the whole sequence instead: what happens from the day a campaign launches to the moment contracts are exchanged, and where the rules that govern it all actually sit.
The campaign that leads up to the day
An auction isn't really a single event - it's the finish line of a marketing campaign that usually runs three to four weeks. During that window the agent holds open homes, publishes a price guide, and fields buyer interest, all while the vendor decides on a reserve. Crucially, a property being 'for auction' means there's no cooling-off period if you buy it that way, so the entire campaign is your window to inspect, review the contract and arrange finance. Miss it, and you're bidding on trust.
Price guide versus reserve - two different numbers
The price guide is what the agent advertises to draw a crowd; the reserve is the confidential minimum the vendor will actually accept. In NSW they're legally distinct, and underquoting - guiding below what the agent reasonably expects - is prohibited, though the gap between guide and result can still be wide in a hot market. The reserve is often not set in stone until the morning of the auction, sometimes adjusted after the agent gauges how many registered bidders turned up. You won't be told the reserve, but you'll know the instant it's met, because the auctioneer announces the property is 'on the market'.
Registration and the rules of the room
What NSW law requires on auction day
- Every bidder must register beforehand with photo ID and receive a bidder's number - no number, no bid
- The auctioneer must read a statement confirming the bidding rules before starting
- The vendor may make one bid, but only if the auctioneer clearly announces it as a vendor bid
- Dummy bidding - fake bids by anyone other than a disclosed vendor bid - is illegal
- A signed contract and deposit are exchanged on the spot; there is no cooling-off period after the hammer falls
Want the process handled by someone who has stood in that crowd hundreds of times?
Talk to a Sydney buyers agentHow the bidding itself unfolds
The auctioneer opens by calling for a bid, and if the room hesitates, may open the market with a single vendor bid to get things moving. From there, bids climb in whatever increments the auctioneer accepts - often larger early, shrinking to smaller rises as the price nears its ceiling. The pace is deliberate theatre: pauses, appeals to the crowd, a slow count near the end. Once bidding clears the reserve, the auctioneer declares the property on the market, and from that point it will sell that day to whoever holds the highest bid when the hammer drops.
What 'passed in' actually means
If bidding stalls below the reserve, the property is 'passed in' rather than sold. This isn't a failure so much as a pivot: the highest bidder is normally given first right to negotiate privately with the agent, on the spot or shortly after, before the vendor opens talks to anyone else. A property passed in on a genuine bid often sells within days by private treaty - which is why the highest bidder's position matters even when the hammer doesn't fall. Around a quarter of Sydney auctions are passed in during softer conditions, so it's a scenario worth understanding in advance, not a surprise.
Tip: if you're the highest bidder when a property passes in, you hold a real negotiating advantage. Don't rush to meet the reserve - the agent has to come to you first, and that conversation is where a buyers agent earns their keep.
The moment of exchange
When the hammer falls in your favour, the sale is immediate and unconditional. You sign the contract there and then and pay the deposit - typically 10 percent, occasionally negotiated lower beforehand with your solicitor - by bank cheque or same-day transfer. Because there's no cooling-off period, your building and pest inspection, contract review and finance approval all need to be locked in before you raise a hand. Settlement then proceeds on the date written into the contract, commonly around six weeks out. There's no going back once you've signed, so the certainty cuts both ways.
Where a buyers agent fits into all this
The mechanics are only half the challenge; the other half is doing your due diligence on a tight campaign clock while staying objective when the bidding turns emotional. A buyers agent runs this constantly - they read the guide against real comparable sales, spot a campaign that's likely to blow past its guide, and can bid on your behalf if you'd rather not stand in the crowd yourself. For interstate or overseas buyers especially, having someone represent you at the auction turns an intimidating ritual into a managed transaction.